Carbon Express 50760 PileDriver Pass Thru Extreme Arrow with Ultra-Slim Design and PTX Half-Out Insert, 250-Sized Grey Shaft Innovative PTX half-out insert reduces the impact of crosswind drift and maximizing downrange kinetic energy for deadly performance Ultra-slim profile design provides ultimate penetration and knockdown power Laser checked for straightness to a remarkable 1/10,000 of an inch Items specifications: 250-Size, 9.36-GPI, 0.390-inch Spine and 0.266-inch Diameter Designed for the archer who wants maximum penetration in a small diameter arrow design and demands precision manufacturing for greater accuracy